Left atrial appendage closure apparatus

ABSTRACT

A left atrial appendage closure apparatus for obstructing the left atrial appendage, comprises a sealing plate and an anchored plate. The sealing plate is in a mesh structure and arranged with a choke membrane inside, in addition, the sealing plate adopts a tubular member for the distal fixation and is connected with the anchor plate by the tubular member. The proximal end of the sealing plate is fixed with a fastener provided with a structure connecting a convey device, meanwhile, the end of the tubular member at the other side away from the end fixed the sealing plate is arranged with a plurality of supporting rods, which are intersecting radially arranged to form the anchored plate.

TECHNICAL FIELD

The present invention relates to an implantable medical device and inparticular relates to a highly effective, repeatable deployment, stablefixed and fatigue resistant left atrial appendage closure apparatuswhich enables to closure the left atrial appendage and obstruct theoutflow of thrombus in the left atrial appendage.

BACKGROUND ART

At present, with the development of the interventional apparatus, manyuntreatable diseases with surgery have been treated. Compared withsurgical treatment, the interventional therapy possesses the advantagesof less trauma, faster recovery and better efficacy. During the pasthalf century, the interventional therapy has been developed rapidly, andvarious kinds of interventional medical devices have also been createdto be used for treating more and more diseases and patients.

Atrial fibrillation (AF) is one of the most common arrhythmias. Apartfrom the discomfort brought by the symptom of palpitation, theoccurrence of the thromboembolism and other complications are the mainhazards of atrial fibrillation. Among the patients with non-valvular andnon-rheumatic atrial fibrillation, about 90% of the thrombus originatedfrom the left atrial appendage. Every year, the thromboembolic eventsand stroke occur in approximately 5% patients with atrial fibrillation.The fatality rate caused by stroke is up to 50%. Therefore, it is ofimportant clinical significance to know how to prevent and treat thestroke caused by atrial fibrillation thromboembolism. At present, theprevention and treatment methods of atrial fibrillation thrombus includesurgeries, drug treatment and interventional therapy. Among all themethods, the occlusion of left atrial appendage by surgical procedurehas not been widely used because of its great trauma and high risk. Atpresent, the most common means to prevent stroke in patients with atrialfibrillation is receiving long-term oral anticoagulant drugs, but theanticoagulant drugs will induce the bleeding risk and about 14% to 44%of patients fail to receive long-term anticoagulant therapy because ofcontraindications. In recent years, a most advanced interventionaltherapy has been developed at home and abroad. Through a tiny catheter,the tailor-made left atrial appendage closure apparatus is implantedinto the left atrial appendage to closure the left atrial appendage andto prevent and treat thrombus events and stroke in patients with atrialfibrillation. This therapy has become the first choice for theprevention and treatment of stroke caused by atrial fibrillation withthe advantages of small trauma, low risk, quick recovery and goodefficacy.

Currently, this kind of instrument can be categorized into braiding,cutting and hybrid types from the view of structure. These types of leftatrial appendage closure apparatus can all be inserted into the leftatrial appendage through catheter intervention to achieve the occlusioneffect of the left atrial appendage, but considerable limitations areexisting among all of them. The left atrial appendages are complex inanatomical structures and different in shape from person to person,including the elliptical and peanut shapes, etc. The inner wall of theleft atrial appendage is uneven, the shape is irregular and the wall isthin, so it is difficult to realize both the non piercement of the walland the solid fixation inside the left atrial appendage without fallingoff, and ultimately achieve the ideal occlusion effect.

For example, the braided-type left atrial appendage closure apparatusrelated to the invention of patents CN1799521A and CN101146570A. Theyanchored the closure apparatus by using the uneven structure on thesurface of the fixation plate of closure apparatus and applying thesealing plate at the opening of the left atrial appendage to achieve theeffect of occlusion. The advantages of this design are simple instructure, less difficulty in processing and low in cost. But the loweranchorage strength of the braided fixation plate makes it difficult toadapt to the different shapes of the left atrial appendage. Even if theanchor hook is sutured on the fixation plate, the fixation plate is alsodifficult to stab into the left atrial appendage wall under thecondition of the extrusion deformation to achieve the stable fixation.Moreover, the shape of the sealing plate will be affected by theextrusion deformation of fixed plate in the left atrial appendage, whichleads to the poor sealing effect.

For example, the cutting-type left atrial appendage closure apparatusrelated to the invention of patents CN1711978A and CN1342056A. Thenickel titanium metal tubes are cut and formed the designed shape bythermal treatment and processing. An outward anchor pin is designed inthe part in contact with the inner wall of the left atrial appendage tostab into the inner wall of the left atrial appendage to achieve stablefixation. Generally speaking, the choke membrane is usually sutured onthe cut-type mesh frame to achieve the effect of left atrial appendageocclusion. The advantage of this structure design is that the wholeclosure apparatus is integrated and rigid, which makes it easy to befixed inside the left atrial appendage. The anchor pins designed areeasy to pierce into the inner wall of the left atrial appendage forstable fixation and prevention of closure apparatus from falling off.However, the cutting type of left atrial appendage closure apparatus islimited in the deformation capacity and fails to adapt to left atrialappendages with various shapes, which limit its application to a greatextent. After the cutting-type left atrial appendage closure apparatusis inserted into the left atrial appendage, the part in the left atrialappendage will usually form a depression with the atrial wall to form anew “left atrial appendage area”, which will increase the risk of newthrombosis. The anchor pins of the cut-type left atrial appendageclosure apparatus are usually stabbed to the left atrium to stabilizethe closure apparatus and prevent the closure apparatus from fallingoff. But the anchor pins stabbed to the left atrium will be stuck to theedge of the sheath wall during the repeated positioning and the closureapparatus recovery to induce the failure of closure apparatus recoveryand repeated positioning.

For example, the hybrid-type left atrial appendage closure apparatusrelated to the invention of patents CN102805654A and CN103099652A. Inthese designs, the sealing plate adopts a braided type and the chokemembrane is usually sutured in the sealing plate to closure the leftatrial appendage. The fixation plate is made by cutting nickel titaniummetal tubes and forms into the designed shape by thermal treatment andprocessing. In the part in contact with the inner wall of the leftatrial appendage, there are outwards anchor pins stabbing into the innerwall of the left auricle to achieve stable fixation. The hybrid-typeleft atrial appendage closure apparatus effectively solves most of theproblems existing in the cut type of left atrial appendage closureapparatus. However, the sealing plate related to CN102805654A possessesa plane structure, which is not suitable for the sealing in arcstructure of the left atrium; in addition, the supporting rods of theanchor plate connect with each other and the deformation of the jointparts is large, which will induce large processing difficulty, poorfatigue resistant performance, brittle in human body and furtherresulting in the risk of cardiac perforation. In addition, an anchor pinin the fixation plate of CN103099652A usually spines to the left atriumto stabilize the closure apparatus and prevent the closure apparatusfrom falling off. But the anchor pins stabbing into the left atrium willbe stuck to the edge of the sheath wall in the process of repeatpositioning and the closure apparatus recovery, which leads to thefailure of repeat positioning and the closure apparatus recovery.Moreover, the fixation plate of the hybrid-type left atrial appendageclosure apparatus usually has large deformation to reverse the directionof the anchor pin, which results in the tension and the shape variableof the fixation plate to reach the extreme of the material. Thisinstrument has poor fatigue strength in permanent implantation, is easyto break and pierce the heart and other tissues to further threaten thelife of the patients.

Moreover, the CN104352261A discloses an improved structure of the leftatrial appendage closure apparatus, in which the connecting plateprovides supporting for the anchor plate to form a rigid structure toenlarge the deformation and increase the processing difficulty. Inaddition, the plane structure of the anchor plate is larger than thediameter of the anchor plate in the processes of unfolding and recovery,which makes it easy to pierce the heart and other tissues and threatenthe life. FIG. 11 is a diagrammatic sketch of the structure in openingstatus.

Therefore, considering the advantages and disadvantages of all kinds ofleft atrial appendage closure apparatus, it is very urgent to develop aleft atrial appendage closure apparatus, which can effectively closurethe left atrial appendage, repeatable deployment, stably fixed andpermanently implanted.

BRIEF SUMMARY OF THE INVENTION

Some embodiments aim to provide an effective, repositionable, stablyfixed and fatigue resistant left atrial appendage closure apparatus forclosuring the left atrial appendage (LAA) and blocking the outflow ofthrombus in the left atrial appendage.

For this purpose, the embodiments of the present invention provide atechnical scheme for providing a left atrial appendage closureapparatus, comprising a sealing plate and an anchor plate connected tothe sealing plate.

The sealing plate is in a mesh structure and arranged with a chokemembrane inside, the sealing plate's distal end is fixed by a tubularmember and is connected with the anchor plate by the other end of thetubular member which is opposite to the end fixed the sealing plate, theproximal end of the sealing plate is fixed with a fastener and has astructure can connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate is arranged with a plurality of supporting rods, thesupporting rods originate from the direction away the sealing plate andthe proximal of the supporting rods cross the center of the tubularmember to the opposite side, the supporting rods are intersectingradially arranged to form the anchored plate, the angle a between thecenter axis of the tubular member and the proximal ends of thesupporting rods is 40-55° and the distal ends of the supporting rods arein an inwardly curved shape.

On the condition that the sealing plate and anchor plate are unfolding,the height of the whole closure apparatus is 12-20 millimeters, theheight of the anchor plate is 9-15 millimeters, and the height of thesealing plate is 3-5 millimeters.

According to the aforementioned preferred structure design, the anchorplate of the left atrial appendage closure apparatus of the embodimentis in a depression shape, which helps to launch and recover the anchorplate with the sheath tube of the convey device. When the sheath tubelaunches or recovers the closure apparatus, the anchor plate indepression shape in the shrinking process has a diameter not larger thanthat in the expansion process, which enables the anchor plate to slowlyshrink into the sheath tube of the convey device so as to avoid thedamage of left atrial appendage and improve the safety efficiency.

Preferably, the length of the distal inward bending part of thesupporting rods is 1-5 millimeters. The number of the supporting rods isnatural number selected from 2 to 50, which is preferred as an oddnumber. The inward bending part of the distal end of at least onesupporting rod has more than one anchor pin on the side near theauricle. The extendable angle between the anchor pin and the supportingrod is 20-45 degrees. On the condition that the anchor plate isunfolding, the anchor plate is capable of against the inner wall of theleft atrial appendage, and the anchor pin is capable of stabbing intothe inner wall of the left atrial appendage to stabilize the fixation ofthe anchor plate in the left atrial appendage, which achieves a goodfixation effect of the anchor plate made of the supporting rods in theinner of the left atrial appendage.

The distal end of the supporting rod is provided with a round ball head,the proximal end of the sealing plate is fixed with the fastener and thestructure of the fastener for connecting with the convey device is ascrew thread structure. The round ball head may prevent the end of thesupporting rod from damaging the left atrial during expansion orrecovering, the arranged screw thread structure is beneficial to thetransmission, expansion and recovery of the left auricle closureapparatus.

The sealing plate is little larger than the anchor plate in diameter, inwhich, on the condition that the sealing plate is 2-6 mm larger than theanchor plate in diameter, it is suitable for single lobe left atrialappendage, and on the condition that the sealing plate is 6-12 mm largerthan the anchor plate in diameter, it is more suitable for the dual-lobeleft atrial appendage. The closure apparatus could fit the structure ofthe left atrial appendage. Therefore, the application range is moreextensive.

In the perspective of processing program, the root of the anchor pin ison the supporting rod, the shape of the anchor pin is laser-cutting outand the angle of the anchor pin is finalizing by thermal treatment withthe mould. The anchor pin expands automatically outwards on thecondition without pressure and retracts onto the supporting rod whenwith pressure. The sealing plate and the anchor plate adopt thememorable alloy material, wherein the nitinol wire is preferred to formthe desired shape by thermal treatment. The tubular member is selectedfrom steel sleeves or other types of alloy sleeves.

The further preferred scheme is that the supporting rods have holes tobe used to suture the PET (polyethylene terephthalate) choke membrane onthe anchor plate to prevent the outflow of thrombus in the left atrialappendage.

The choke membrane is as an unmodified or chemically modified PET chokemembrane.

The PET choke membrane could be a chemically modified PET chokemembrane, which has an amide group by an exchange reaction with an estergroup. The contact angle of the chemically modified PET choke membraneis less than 90 degrees, which enhances the hydrophilicity. The membranesurface chemical treatment of the choke membrane induces the surfacenegative ionization, which not only reduces the platelet adhesion on thesurface of the sealing plate, but also improves the hydrophilicity andbiological compatibility of the choke membrane as well as achieves rapidendothelialization. The endothelialization degree in a short period ismuch higher than that of the unmodified PET choke membrane, whichreduces the closure apparatus associated thrombosis risks.

Specifically, the PET choke membrane makes use of the reaction toreplace the ester group for the amide group to graft the molecule withsodium sulfonate group on the surface of the choke membrane, so that thePET choke membrane becomes electronegative. This kind of PET chokemembrane enables to adsorb the toluidine blue dye with positiveelectrical charge.

The chemical modification method of the PET choke membrane is asfollows: placing a PET choke membrane in a proper container, adding themixed solvent of water and 1, 4-dioxane, adding alkane with terminalgroup of amino group and sulfonic group respectively, and catalyst,stirring for 2-24 hours at 50-100 ° C. and removing the choke membraneafter the reaction.

The mentioned alkane with the sulfonic group is selected from 3-aminopropane sulfonic acid, 4-amino butane sulfonic acid, 5-amidopentanesulfonic acid and 6-amino hexane sulfonic acid.

The mentioned catalyst is selected from sodium hydroxide, potassiumhydroxide or ammonia water.

A more specific preferred choice: the volume ratio of water to 1,4-dioxaneis is 5:1. After the reaction is finished, the choke membraneis removed and washed repeatedly by deionized water and absolutealcohol.

For example, a chemical modification method of a PET choke membrane isas following: placing 50 pieces of PET choke membranes in a 250 mL ofround bottom flask, adding 200 mL of mixed solvent of water and 1,4-dioxane with the volume ratio of 5:1, adding 0.5 g of alkane withterminal group of amino group and sulfonic group respectively, and 1 gof catalyst, stirring for 2-24 hours at 50-100° C., removing the chokemembrane after reaction, and washing 5 times repeatedly by deionizedwater and anhydrous alcohol.

Compared with the existing technology, the embodiments of the presentinvention possess the following advantages:

The anchor plate of the left atrial appendage closure apparatusaccording to the invention is in a depression shape, which helps thesheath tube of the convey device to launch and recover the anchoredplate. When the closure apparatus is launched or recovered by the sheathtube, the anchor plate in the depression shape has the smaller diameterin the shrinking process than in the expansion process, which enablesthe anchor plate to slowly shrink into the sheath tube of the conveydevice so as to avoid the damage of left atrial appendage and improvethe safety efficiency.

The anchor plate of the left atrial appendage closure apparatusaccording to the invention is mild in structure deformation, stable, andis of excellent fatigue resistance performance for permanentimplantation and adaptable to the left atrial appendage cavity withvarious shapes and sizes.

The two-stage design of the left atrial appendage closure apparatusaccording to the present invention enables the closure apparatus toadapt to various forms and dimensions of the left atrial appendage.

The left atrial appendage closure apparatus according to the inventionhas the advantages of stable anchorage and effective occlusion of leftatrial appendage.

The left atrial appendage closure apparatus according to the inventionis applicable to not only closure the single lobe left atrial appendage,but also closure the dual-lobe left atrial appendage.

The left atrial appendage closure apparatus according to the inventionis repositionable. In some cases, if the placement is not good enough,the closure apparatus can be recovered to the sheath tube, andrepositioned on the conditions without removing from a pushing rod untilthe satisfactory anchoring and occlusion effects are achieved, whichgreatly reduces the surgery risks.

The left atrial appendage closure apparatus according to the inventioncan use a small conveying system to further reduce the damage to theblood vessel of the convey devices in the surgery process.

The left atrial appendage closure apparatus according to the inventionis flexibly connected with the pushing rod, which greatly reduces thetension exerted by the convey device such as the pushing rod to theclosure apparatus and makes the placement of the closure apparatus moreaccurate and precise.

The choke membrane of the left atrial appendage closure apparatusaccording to the invention is chemically treated to generate thenegative surface ionization, which not only reduces the plateletadhesion on the surface of the sealing plate, but also improve thehydrophilicity and biological compatibility of the choke membrane aswell as achieves rapid endothelialization. The endothelialization degreein a short period of time is much higher than that of the unmodified PETchoke membrane, which reduces the closure apparatus associatedthrombosis risks.

The present invention will become clearer with the following descriptionin combination with the accompanying drawings, which are used to explainthe embodiments of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagrammatic sketch of a preferred embodiment of the leftatrial appendage closure apparatus according to the invention;

FIG. 2 is a diagrammatic sketch of the third embodiment of the leftatrial appendage closure apparatus according to the invention;

FIG. 3 is a diagrammatic sketch of the fourth embodiment of the leftatrial appendage closure apparatus according to the invention;

In FIG. 4, FIG. 4a is a position diagrammatic sketch of the fifthembodiment of the left atrial appendage closure apparatus displayed inFIG. 1 in the anatomical structure of the single lobe left atrialappendage; FIG. 4b is a position diagrammatic sketch of the fifthembodiment of the left atrial appendage closure apparatus displayed inFIG. 1 in the anatomical structure of the dual-lobe left atrialappendage; FIG. 4c is a position diagrammatic sketch of the fifthembodiment of the left atrial appendage closure apparatus displayed inFIG. 3 in the anatomical structure of the dual-lobe left atrialappendage;

In FIG. 5, FIG. 5a is a schematic diagram of the status that the anchorplate of the left atrial appendage closure apparatus as shown in FIG. 1is just going out of the sheath tube of the convey device; FIG. 5b is aschematic diagram of the status that the anchor plate of the left atrialappendage closure apparatus as shown in FIG. 1 is going out of thesheath tube of the convey device; FIG. 5c is a schematic diagram of thestatus that the anchor plate of the left atrial appendage closureapparatus as shown in FIG. 1 is completely going out of the sheath tubeof the convey device;

FIG. 6 is a schematic diagram of the chemical reaction equation for thechemical modification of the choke membrane in the left atrial appendageclosure apparatus according to the embodiments of the present invention,in which n=500-5000, R: CH₂, C₂H₄, C₃H₆ or C₄H₈.

FIG. 7 is a dyeing experiment schematic diagram of the chemicalmodification of the choke membrane in the left atrial appendage closureapparatus according to the embodiments of the present invention.

FIG. 8 is a schematic diagram of the contact angle test after chemicalmodification of the choke membrane of the left atrial appendage closureapparatus according to the embodiments of the present invention. LA isthe left contact angle and RA is the right contact angle.

FIG. 9 is a histogram of the contact angle test results of the ePTFE(expanded polytetrafluoroethylene) reference substance, choke membranebefore chemical modification, and choke membrane of the left atrialappendage with different chemical modification time according to theembodiments of the invention.

FIG. 10 is a postoperatively anatomic image. FIG. 10a and FIG. 10b arerespectively the anatomic image 1 day and 1 month after the surgery.

FIG. 11 is the unfolded or recovery schematic diagram of the closureapparatus according to CN104352261A.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS OF THE INVENTION

The embodiments of the invention were described with references to theaccompanying drawings. The similar element symbols in the attacheddrawings represented the similar elements.

Embodiment 1

FIG. 1 described a left atrial appendage closure apparatus, including asealing plate 106 and an anchor plate 101 connected to the sealingplate.

The sealing plate was in a mesh structure and arranged with a chokemembrane 108 inside, the sealing plate's distal end was fixed by atubular member 109 and was connected with the anchor plate by the otherend of the tubular member which was opposite to the end fixed thesealing plate, the proximal end of the sealing plate was fixed with afastener 110 and had a structure can connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate was arranged with a plurality of supporting rods 102,the supporting rods originated from the direction away the sealing plateand the proximal ends 102 b of the supporting rods crossed the tubularmember center to the opposite side, the supporting rods wereintersecting radially arranged to form the anchor plate 101. The angle abetween the center axis of the tubular member and the proximal ends 102b of the supporting rods was 40-55° and the distal ends 102 a of thesupporting rods were in an inwardly curved shape.

Embodiment 2

A left atrial appendage closure apparatus described in FIG. 1, includinga sealing plate 106 and an anchor plate 101 connected to the sealingplate.

The sealing plate was in a mesh structure and arranged with a chokemembrane 108 inside, the sealing plate's distal end was fixed by atubular member 109 and was connected with the anchor plate by the otherend of the tubular member which was opposite to the end fixed thesealing plate, the proximal end of the sealing plate was fixed with afastener 110 and had a structure which could connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate was arranged with a plurality of supporting rods 102,the supporting rods originated from the direction away the sealing plateand the proximal ends 102 b of the supporting rods crossed the tubularmember center to the opposite side, the supporting rods wereintersecting radially arranged to form the anchor plate 101. The angle abetween the center axis of the tubular member and the proximal ends 102b of the supporting rods was 40-55° and the distal ends 102 a of thesupporting rods were in an inwardly curved shape.

When the sealing plate and the anchor plate were unfolding, the heightof the whole closure apparatus was 12-20 millimeters, the height of theanchor plate was 9-15 millimeters, and the height of the sealing platewas 3-5 millimeters.

Embodiment 3

A left atrial appendage closure apparatus described in FIG. 2, includinga sealing plate 106 and an anchor plate 101 connected to the sealingplate.

The sealing plate was in a mesh structure and arranged with a chokemembrane 108 inside, the sealing plate's distal end was fixed by atubular member 109 and was connected with the anchor plate by the otherend of the tubular member which was opposite to the end fixed thesealing plate, the proximal end of the sealing plate was fixed with afastener 110 and had a structure which could connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate was arranged with a plurality of supporting rods 102,the supporting rods originated from the direction away the sealing plateand the proximal ends 102 b of the supporting rods crossed the tubularmember center to the opposite side, the supporting rods wereintersecting radially arranged to form the anchor plate 101. The angle abetween the center axis of the tubular member and the proximal ends 102b of the supporting rods was 40-55° and the distal ends 102 a of thesupporting rods were in an inwardly curved shape.

The length of the inward bending part of the distal ends 102 a of thesupporting rods was 1-5 millimeters. The number of the supporting rodswas 6. The inward bending part of the distal end of at least onesupporting rod had more than one anchor pin 104 on the side near theauricle. The extendable angle between the anchor pin and the supportingrod could be 20-45 degrees. When the anchor plate was unfolding, theanchor plate was against the inner wall of the left atrial appendage,and the anchor pin stabbed into the inner wall of the left atrialappendage to stabilize the fixation of the anchor plate in the leftatrial appendage.

The distal ends of the supporting rods were provided with round ballheads 111, and the proximal end of the sealing plate was fixed with thefastener, and the structure of the fastener for connecting with theconvey device was a screw thread structure.

Embodiment 4

A left atrial appendage closure apparatus described in FIG. 2, includinga sealing plate 106 and an anchor plate 101 connected to the sealingplate.

The sealing plate was in a mesh structure and arranged with a chokemembrane 108 inside, the sealing plate's distal end was fixed by atubular member 109 and was connected with the anchor plate by the otherend of the tubular member which was opposite to the end fixed thesealing plate, the proximal end of the sealing plate was fixed with afastener 110 and had a structure which could connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate was arranged with a plurality of supporting rods 102,the supporting rods originated from the direction away the sealing plateand the proximal ends 102 b of the supporting rods crossed the tubularmember center to the opposite side, the supporting rods wereintersecting radially arranged to form the anchor plate 101. The angle abetween the center axis of the tubular member and the proximal ends 102b of the supporting rods was 40-55° and the distal ends 102 a of thesupporting rods were in an inwardly curved shape.

The length of the inward bending part of the distal ends 102 a of thesupporting rods was 1-5 millimeters. The number of the supporting rodswas 6. The inward bending part of the distal end of at least onesupporting rod had more than one anchor pin 104 on the side near theauricle. The extendable angle between the anchor pin and the supportingrod could be 20-45 degrees. When the anchor plate was unfolding, theanchor plate was against the inner wall of the left atrial appendage,and the anchor pin stabbed into the inner wall of the left atrialappendage to stabilize the fixation of the anchor plate in the leftatrial appendage.

The distal ends of the supporting rods were provided with round ballheads 111, and the proximal end of the sealing plate was fixed with thefastener, and the structure of the fastener for connecting with theconvey device was a screw thread structure.

As shown in FIG. 3, the supporting rods could also be provided withholes to be used to suture the PET (polyethylene terephthalate) chokemembrane on the anchor plate to prevent the outflow of thrombus in theleft atrial appendage.

Embodiment 5

A left atrial appendage closure apparatus described in FIG. 2, includinga sealing plate 106 and an anchor plate 101 connected to the sealingplate.

The sealing plate was in a mesh structure and arranged with a chokemembrane 108 inside, the sealing plate's distal end was fixed by atubular member 109 and was connected with the anchor plate by the otherend of the tubular member which was opposite to the end fixed thesealing plate, the proximal end of the sealing plate was fixed with afastener 110 and had a structure which could connect a convey device.

The end of the tubular member at the other side away from the end fixedthe sealing plate was arranged with a plurality of supporting rods 102,the supporting rods originated from the direction away the sealing plateand the proximal ends 102 b of the supporting rods crossed the tubularmember center to the opposite side, the supporting rods wereintersecting radially arranged to form the anchor plate 101. The angle abetween the center axis of the tubular member and the proximal ends 102b of the supporting rods was 40-55° and the distal ends 102 a of thesupporting rods were in an inwardly curved shape.

The length of the inward bending part of the distal ends 102 a of thesupporting rods was 1-5 millimeters. The number of the supporting rodswas 6. The inward bending part of the distal end of at least onesupporting rod had more than one anchor pin 104 on the side near theauricle. The extendable angle between the anchor pin and the supportingrod could be 20-45 degrees. When the anchor plate was unfolding, theanchor plate was against the inner wall of the left atrial appendage,and the anchor pin stabbed into the inner wall of the left atrialappendage to stabilize the fixation of the anchor plate in the leftatrial appendage.

The distal ends of the supporting rods were provided with round ballheads 111, and the proximal end of the sealing plate was fixed with abolt head, and the structure of the fastener for connecting with theconvey device was a screw thread structure.

As shown in FIG. 4a , the sealing plate was little larger than theanchor plate in diameter, in which, if the sealing plate was 2-6 mmlarger than the anchor plate in diameter, the closure apparatus wassuitable for single lobe left atrial appendage.

But the dimension above was difficult to completely seal the dual-lobeleft atrial appendage as displayed in FIG. 4b . Therefore, anotherpreferred scheme had been shown in FIG. 4c , the sealing plate waslittle larger than the anchor plate in diameter, in which, if thesealing plate was 6-12 mm larger than the anchor plate in diameter, theclosure apparatus was more suitable for the dual-lobe left atrialappendage.

Embodiment 6

As shown in FIGS. 5a, 5b and 5c , the anchor plate 101 had the followingcharacteristics in the processes of entering the sheath tube 115 of theconvey device and going out from the sheath tube 115: in order toclearly demonstrate the processes for the anchor plate 101 to enter andexit the sheath tube, the number of the supporting rods 102 of theanchor plate 101 had been simplified to 2 in FIGS. 5a, 5b and 5c , thesupporting rods 102 were straightened in the sheath tube and were in across shape, the anchor pins 104 were towards to oblique medialdirection opposite to the central end 107 of the tubular member. Theinner wall of the sheath tube would not be scratched during the pushingprocess in the sheath tube 115. Under the thrust of the pushing rod, theelbows of the distal ends 102 a of the supporting rods were slowlypushed out of the sheath 115 (FIG. 5a ) and expand along the directionA. With the continuous pushing of the pushing rod, the supporting rods102 continued to expand along the direction A as the status displayed inFIG. 5b . At this point, the anchor pins 104 turned about 90 degrees tonearly perpendicular to the pushing rod. The pushing rod continued toexert the impetus and push the anchor plate 101 completely out of thesheath 115, and the supporting rods 102 continued to expand along thedirection A as the status displayed in FIG. 5c . At this time, theanchor plate 101 was fully unfolded, the anchor pins 104 were turnedover about 90 degrees again to locate outside the anchor plate 101 andface towards the oblique lateral direction of the central end 107, tostab into the inner wall of the left atrial appendage. The closureapparatus was fixed in the left atrial appendage cavity.

The process of recovering the anchor plate 101 was the opposite of eachphase of the process of pushing the anchor plate 101 outside the sheathtube 115. The anchor plate 101 was pulled into the sheath tube 115 alongthe direction B by the pushing rod, wherein the remarkablecharacteristic was that the anchor pins 104 turned towards the obliquemedial direction opposite to the central end 107 from the obliquelateral direction of the central end 107 in the expansion process. Thisprocess ensured that the anchorage pins 104 did not scrape the wall ofthe left atrial appendage and entered the sheath tube 115 smoothly. Theleft atrial appendage closure apparatus in this embodiment was not onlyable to ensure the repositioning function of the anchor plate 101 in theleft atrial appendage, but also greatly reduced the damage to the leftatrial appendage wall and reduced the risk and complications of surgery.

Embodiment 7 A Processing Scheme

As shown in FIGS. 1, 2 and 3, the left atrial appendage closureapparatus related to the invention included the sealing plate 106 andthe anchor plate 101 connected with the sealing plate 106, wherein thesealing plate 106 was woven into a mesh structure with nitinol wires andfinalized to plate shape by thermal treatment, both the ends of thesealing plate were fixed with the steel sleeve 109 and the fastener 110respectively, one end of the sealing plate 106 was linked to the anchorplate 101 with the steel sleeve and the other end was connected with thepushing rod of the convey device by a screw thread structure. Thediameter of the sealing plate 106 was about 2-6 mm larger than that ofthe anchor plate 101, and the inside of the sealing plate 106 wassutured with the chemically modified PET choke membrane 108. The anchorplate 101 was made up of a multiple of supporting rods 102 cut from anitinol tube, and was treated by thermal treatment with the mould toform the shape shown in the figures. The central end 107 of the anchorplate 101 was welded with the sealing plate 106. According to therequirements of the actual mechanical performance and specifications,the number of supporting rods could be changed. The supporting rodsemanated from one inner side of the circle central end 107, crossed thecenter of the central end 107 to the opposite side, and were bent. Thesupporting rods were arranged in a cross radial way. Holes could also bearranged on the supporting rods 102 to suture the PET choke membrane onthe anchor plate 101 to prevent the outflow of the thrombus in the leftatrial appendage. On the supporting rods 102, the shape of the anchorpins 104 was cut out by laser and the angle of the anchor pins 104 wasfinalizing by thermal treatment of the mould. The anchor pins 104obliqued laterally and faced towards the sealing plate 106. The root ofthe anchor pins 104 was on the supporting rods 102, the anchor pins 104opened outward automatically without pressure and were recovered to thesupporting rods 102 when with pressure. The distal ends 102 a of thesupporting rods were curved inward. A spherical head 111 could bearranged at the distal end of the supporting rod 102 to prevent fromscratching the inner auricle when the anchor plate 101 was pushed out ofthe sheath.

Embodiment 8

The PET choke membrane sutured in the sealing plate of the left atrialappendage closure apparatus according to the embodiment was a chemicallymodified choke membrane. As shown in FIG. 6, the PET choke membrane tookadvantages of the reaction to exchange the ester group for an amidegroup to graft the molecule with sodium sulfonate group on one side ontothe surface of the choke membrane, and the specific operation was asfollows:

50 pieces (50×50 mm²) of PET choke membrane were placed in a 250 mL ofround bottom flask, 200 mL of mixed solvent of water and 1, 4-dioxanewith the volume ratio of 5:1 were added, 0.5 g of alkane with terminalgroup of amino group and sulfonic group, such as 3-aminopropanesulfonicacid, 4-aminobutanesulfonic acid, 5-aminopentanesulfonic acid or6-aminohexane sulfonic acid was added respectively, then 1 g catalyst,such as sodium hydroxide, potassium hydroxide or ammonia water was add.The mixture was stirred for 2-24 hours at 50-100° C., the choke membranewas removed after the reaction, and the resulting solution was washed 5times repeatedly by deionized water and anhydrous alcohol.

As shown in FIG. 7, the PET choke membrane after the chemical reactionwas immersed in the toluidine blue dye with positive electrical chargeand removed immediately. By many experiments, it was found that the PETchoke membrane without chemical modification did not adsorb thetoluidine blue dye with positive electrical charge and the adsorbedquantity of the toluidine blue dye also gradually increased with thegradual increasing of the chemical modification time of the PET chokemembrane.

According to the contact angle test results shown in FIGS. 8 and 9, thecontact angle between the chemically modified PET choke membrane and thewater droplet was 76.5±3 degrees (as displayed in PET-8 h histogram),which was 41 degrees smaller than that of the unmodified PET chokemembrane, and 51 smaller than that of the super hydrophobic ePTFE film.According to the test results, the hydrophilicity of the modified PETfilm was greatly enhanced, which was beneficial to improve thehydrophilicity and biocompatibility of the choke membrane, to achieverapid endothelialization and to reduce the risk of thrombosis associatedwith the closure apparatus.

Embodiment 9. Animal Experiment

The closure apparatus with the chemical modified PET choke membrane inthe embodiment according to the invention was adopted and theexperimental method was as follows:

All the experimental dogs received percutaneous left atrial appendageocclusion under general anesthesia. They started fasting 12 h before thesurgery and were tied up on the operating table after anesthesia, thetracheal intubation was conducted to connect the respirator formechanical ventilation with indwelling transesophageal ultrasound probe.The electrocardiogram monitoring was connected and venous access in theleft lower extremities was established. If the anatomic abnormalities ofthe heart were observed in the transesophageal echocardiogram, thesurgery would be stopped and the other experimental dog was replaced.For dogs with normal heart anatomy, the shape of their left atrialappendage was observed by transesophageal echocardiography and thediameter of left atrial appendage was measured to select the closureapparatus with a diameter about 15-35% larger than the measureddiameter. The routine disinfection was performed and the sterile towelswere spread. The right femoral artery and vein were punctured with theTelma puncture suit, and the 6 F femoral sheath was retained. Throughthe femoral artery sheath, the 5 F pigtail catheter was sent to theaortic sinus to mark the position of the aortic sinus to avoid atrialseptal puncture into the aortic sinus. Through the femoral vein sheath,the atrial septal puncture needle (SL1, St Jude Medical, US) and thematched atrial septal puncture sheath were sent into to complete thetransseptal puncture under the guidance of the transesophagealechocardiography, after successful puncture, 80-100U/kg of heparin wasgiven, and the atrial septal puncture needle was withdrawn, the longexchange steel wire was sent to the left pulmonary vein to exchange 8-10F closure apparatus delivery sheath to the opening part of the leftatrial appendage, and the pigtail catheter was sent to left atrialappendage for conducting the left atrial appendage angiography andmeasuring the opening diameter of the left atrial, the sealing plate ofthe closure apparatus with the diameter about 15-35% larger than themeasurement value was selected in combination with the transesophagealechocardiography results, and the closure strategy was determinedaccording to the lobe form of the left atrial appendage. The sealingplate selected was fixed on the head of the pushing rod by a nut, whenthe air in the closure apparatus and the conveying sheath was exhausted,slowly forwarded the pushing rod and pushed part of the anchor plate outof the delivery sheath before entering the opening of the left atrialappendage. The conveying sheath and the pushing rod as whole were pushedto the anchoring area of the left atrial appendage, and when their headreached the anchoring area of the opening of the left atrial appendage,fixed the pushing rod and withdrew the conveying sheath gradually, theclosure apparatus deployed was observed by the transesophagealechocardiography and angiography of left atrial appendage, while thepushing and pulling test were performed to check whether the deployed ofthe closure apparatus was firm and stable. If the closure apparatus wasin the proper position and the fixation was firm, the closure apparatuswould be released. If the complete occlusion failed or the extensionshape of the closure apparatus was improper, the closure apparatusshould be completely recycled into the conveying sheath to try again tobe expanded until the ideal sealing effect was achieved, then theclosure apparatus could be released. After the surgery, the experimentaldogs routinely took aspirin and were followed up regularly. Theanatomical images (FIGS. 10a and 10b ) on the 1st day and 1 month aftersurgery displayed that in the 1-2 months, the endothelial cells wereuniformly endothelialized on the closure apparatus and there was noobvious thrombosis forming, which was significantly more effective thanthe existing technology in endothelialization and thrombosis inhibition.

Therefore, the embodiments according the present invention has thefollowing advantages:

The anchor plate of the left atrial appendage closure apparatusaccording to the invention is in a depression shape, which helps thesheath tube of the convey device to launch and recover the anchoredplate. When the closure apparatus is launched or recovered by the sheathtube, the anchor plate in the depression shape has the smaller diameterin the shrinking process than in the expansion process, which enablesthe anchor plate to slowly shrink into the sheath tube of the conveydevice so as to avoid the damage of left atrial appendage and improvethe safety efficiency.

The anchor plate of the left atrial appendage closure apparatusaccording to the invention is mild in structure deformation, stable, andis of excellent fatigue resistance performance for permanentimplantation and adaptable to the left atrial appendage cavity withvarious shapes and sizes.

The two-stage design of the left atrial appendage closure apparatusaccording to the present invention enables the closure apparatus toadapt to various forms and dimensions of the left atrial appendage.

The left atrial appendage closure apparatus according to the inventionhas the advantages of stable anchorage and effective occlusion of leftatrial appendage.

The left atrial appendage closure apparatus according to the inventionis applicable to not only closure the single lobe left atrial appendage,but also closure the dual-lobe left atrial appendage.

The left atrial appendage closure apparatus according to the inventioncan be repeatedly positioned. In some cases, if the placement is notgood enough and without releasing the convey device, such as the pushingrod, the closure apparatus can be recovered to the sheath tube andrepositioned until the satisfactory anchoring and occlusion effects areachieved, which greatly reduces the surgery risks.

The left atrial appendage closure apparatus according to the inventioncan use a small conveying system to further reduce the damage to theblood vessel of the convey devices in the surgery process.

The left atrial appendage closure apparatus according to the inventionis flexibly connected with the pushing rod, which greatly reduces thetension exerted by the pushing rod to the closure apparatus and makesthe placement of the closure apparatus more accurate and precise.

The choke membrane of the left atrial appendage closure apparatusaccording to the invention is chemically treated to generate thenegative surface ionization, which not only reduces the plateletadhesion on the surface of the sealing plate, but also improve thehydrophilicity and biological compatibility of the choke membrane aswell as achieves rapid endothelialization, which reduces the closureapparatus associated thrombosis risks.

The above mentioned is only a better embodiment of the presentinvention, and should not be used to restrict the invention. Anymodification, equal substitution and improvement within the spirit andprinciples of the invention should be included in the protection scopeof the invention.

1. A left atrial appendage closure apparatus, comprising: a sealingplate and an anchor plate connected to the sealing plate, the sealingplate is in a mesh structure and arranged with a choke membrane inside,the sealing plate's distal end is fixed by a tubular member and isconnected with the anchor plate by the other end of the tubular memberwhich is opposite to the end fixed the sealing plate, the proximal endof the sealing plate is fixed with a fastener and has a structure canconnect a convey device; the end of the tubular member at the other sideaway from the end fixed the sealing plate is arranged with a pluralityof supporting rods, the supporting rods originate from the directionaway the sealing plate and the proximal of the supporting rods cross thecenter of the tubular member to the opposite side, the supporting rodsare intersecting radially arranged to form the anchored plate, the anglea between the center axis of the tubular member and the proximal ends ofthe supporting rods is 40-55° and the distal ends of the supporting rodsare in an inwardly curved shape.
 2. The left atrial appendage closureapparatus according to claim 1, on the condition that the sealing plateand anchor plate are unfolding, the height of the whole closureapparatus is 12-20 millimeters, the height of the anchor plate is 9-15millimeters, and the height of the sealing plate is 3-5 millimeters. 3.The left atrial appendage closure apparatus according to claim 1,wherein the length of the distal inward bending part of the supportingrods is 1-5 millimeters.
 4. The left atrial appendage closure apparatusaccording to claim 1, wherein the number of the supporting rods isnatural number selected from 2-50, which is preferred as an odd number.5. The left atrial appendage closure apparatus according to claim 1,wherein the distal inward bending part of at least one supporting rodhas more than one anchor pin on the side near the auricle, theextendable angle between the anchor pin and the supporting rod is 20-45degrees.
 6. The left atrial appendage closure apparatus according toclaim 5, on the condition that the anchor plate is unfolding, the anchorplate is capable of against the inner wall of the left atrial appendage,and the anchor pin is capable of stabbing into the inner wall of theleft atrial appendage to stabilize the fixation of the anchor plate inthe left atrial appendage.
 7. The left atrial appendage closureapparatus according to claim 5, the root of the anchor pin is on thesupporting rod, the shape of the anchor pin is laser-cutting out and theangle of the anchor pin is finalizing by thermal treatment with themould, the anchor pin expands automatically outwards without pressureand retracts onto the supporting rod when with pressure.
 8. The leftatrial appendage closure apparatus according to claim 1, wherein thereis a round ball head at the distal end of the supporting rod, thestructure of the fastener for connecting with the convey device is ascrew thread structure.
 9. The left atrial appendage closure apparatusaccording to claim 1, the diameter of the sealing plate is little largerthan that of the anchored plate, wherein the diameter of the sealingplate is 2-6 mm or 6-12 mm larger than that of the anchored plate. 10.The left atrial appendage closure apparatus according to claim 1, thesealing plate adopts the memorable alloy material, wherein the nitinolwire is preferred to form the desired shape by thermal treatment, thetubular member is selected from steel sleeves or other types of alloysleeves.
 11. The left atrial appendage closure apparatus according toclaim 1, wherein the supporting rods have holes to be used to suture thechoke membrane on the anchor plate to prevent the outflow of thrombus inthe left atrial appendage.
 12. The left atrial appendage closureapparatus according to claim 1, wherein the choke membrane is anunmodified or chemically modified PET choke membrane.
 13. The leftatrial appendage closure apparatus according to claim 12, wherein thePET choke membrane is a chemically modified PET choke membrane, whichhas an amide group by an exchange reaction with an ester group, and thecontact angle of the chemically modified PET choke membrane is less than90 degrees, which enhances the hydrophilicity.
 14. The left atrialappendage closure apparatus according to claim 13, wherein the reactiongraft the molecule with sodium sulfonate group onto the surface of thechoke membrane, so that the surface of the PET choke membrane iselectronegative.
 15. The left atrial appendage closure apparatusaccording to claim 13, wherein the chemical modification method of PETchoke membrane comprise the steps: placing a PET choke membrane in aproper container, adding the mixed solvent of water and 1, 4-dioxane,then adding alkane with terminal group of amino group and sulfonic grouprespectively, and catalyst, stirring for 2-24 hours at 50-100 ° C. andremoving the choke membrane after the reaction.
 16. The left atrialappendage closure apparatus according to claim 15, wherein the alkane isselected from 3-amino propane sulfonic acid, 4-amino butane sulfonicacid, 5-amidopentane sulfonic acid and 6-amino hexane sulfonic acid, thecatalyst is selected from sodium hydroxide, potassium hydroxide andammonia water.
 17. The left atrial appendage closure apparatus accordingto claim 15, wherein the volume ratio of water to 1, 4-dioxane is 5:1,the choke membrane is removed and washed repeatedly by deionized waterand absolute alcohol after the reaction is finished.